Regulation of electric motors



(No Model.)

L. S. HARRIS.

REGULATION OF ELECTRIC MOTORS. No. 891,319. Patented 001;. 16, 1888.

flttorney Nv PETERS. Phnm-Lvmugmpher, Washmgwn, D. C

VVITJVESSES. dw dkiw 7%. 75 fifll LANDER S. HARRIS, OF DETROIT, MICHIGAN.

ULA'i'lON or stsoraac MOTOQS.

r;2EGIPICATION forming part of Letters Patent No. 391,819, dated Qctcber 16, $888.

(No model.)

To aZZ whom it may concern/.-

Be it known that I, LANDER S. Hannrs, a citizen of the United States, residing at Detroit, county of \Vayne, State of Michigan, have invented certain new and useful Improvements in Motors; and I declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, relerence being had to the accent panying drawings, which form a part of this specification.

In the drawings, Figure 1 is a view in side elevation showing parts in section of an electric motor involving my invention. Fig. 2 is an end elevation of the same. Fig. 4 is a diagrammatic view illustrating the direction of the currents and the switch mechanism. Fig. 3is a sectional view transversely of the shalt through the safetyiuses.

It is the purpose of my invention to produce an electric motor which may be made to run faster or slower without varying the amount of current passing through the fields, and

without varying materially, if any, the resist ance on the main line, the said results being accomplished by a peculiar winding of the machine, whereby the current is shifted through coarser or finer wire, thus producing the magnetic ciIects necessary to impart to the machine a greater or less speed and power, as it may be desirable to vary the same.

In carrying out my invention, A represents Y the field-magnets; B, the pole pieces; G, the

armature; D, the commutator; E, the commututor-brushes.

F is a switch for varying the motion of the motor.

G represents a series of fusible strips, the said strips being arranged upon the armature and shaft so that each bobbin of the armature shall have one of these strips interposed between it and its commutator segment or segments.

H are the binding-posts.

J represents the main line through which the current enters, and J the line through which it leaves the motor.

K. represents a winding of coarse wire next adjacent to the cores of the field-magnets. L is an adjacentwinding of finer wire, and M M represent the outer winding ofstill finer wire. These windings are all in the same direction around the field-magnets, and the last-mentioned finest grade of wire 31 M is divided into two parts, for a reason hereinafter explained. The relative grades of wire which I have employed are No. 23 for the finest, No. 20 for the next coarser grade, and No.16 for the coarsest grade; but i would have it understood that I am not limited to the above sizes of wire, but any wires of dii'ferent gage may be employed.

The operation of this device is as follows, reference being had to the diagram, Fig. 4.: Ne will presume the switch 1 to be standing straight up and down on the diagram, with that end marked l lowermost. The machine will now be inert and entirely cut oil from the current. Now, if it is desired to start the mo tor and have it run at a low rate of speed, the switch is turned to the right until its lower end rests upon the terminal F and its upper end connects the two terininalsff. Current now entering from the main line at J passes thence to the middle of the lever and downward to the terminal F, thence out over the line wire M around the iicldmagnets, and thence back to the terminal f. Thence it crosses over on the switclrlever to the terminalf, thence oil through the fine wire 3i around the field-mag nets, thence to the armature O, and from the armature off on the main line again at J. This, it will be observed, brings both ofthe windings of fine wire into the circuit, and there is given to the motor a moderate motion, and energy is developed, due to the magnetic conditions set up by the entire current from theinain linein passing through said windings of line wire. Now suppose it is desired. to give to the motor a greater speed, the switehiever is turned to the right until one end rests upon the terminal l and the other end rests upon both terminalsf and f Current now entering from J passes to the switch, thence to h over the coarser wire L, thence around the fields and back through the terminalf to the terminal f thence across the switch-lever to the terminal), thence down to the terminal F and through the fine wire M and through the terminal f, thence through the terminalf, the insulated connection f on the lever, and the terminal f to the terminal f thence to the arm ature,and from the armature off on the line at J. It is thus observed that the current in this location of the switch-lever is caused to take in one-half of the line wire, or that indi cated by M, and the next coarser grade, L, and the motion of the armature and the energy developed are proportioned to the magnetic conditions developed by the passage of the entire current through these two windings of wire. Now, to obtain the highest'speed and greatest energy of the motor, the switch is turned into the position shown in the drawings, so that it connects the terminal F" with the two terminalsf f The current, entering as before, passes through the terminal F, thence through the coarsest grade of wire K, through the fields back to the terminal F and through the next finer grade, L, thence to the terminal j, across to the terminal f thence to the armature, and from the armature to the main line again at J. It is thus seen that by this position of the switch the current is caused to travel through the coarsest and next grade of wire without passing through the two finest grades M M, and the motion and energy of the motor are such as are developed by the entire current passing through these two grades of wire in the motor.

It will be seen from the foregoing construction that the necessity for resistance-boxes as a means of varying the speed of the machine is entirely obviated. So, also, the whole mechanism for changing the speed is located within the motor itself. Moreover, in changing from one speed to another the change is accomplished without varying in any respect the amount of the current passing through the motor; consequently there is not only no variation on the main line, but no variation in the current in the motor itself.

The switch F is preferably located on the motor itselfin its ordinary construction; but if for any reason the operator should desire to locate the switch adjacent to his work instead of on the machine itselfit is only necessary to lead the wires to the said switch at any said location.

The field-magnets and their polepieces are preferably adjusted about the armature in sub stantially the manner indicated in the drawings, so as to quite closely embrace the armature throughout and yet permit the armature to rotate practically in the plane of the fieldmagnets; but if for any reason it should be found desirable in order to decrease the space occupied by the machine the armature-shaft might be passed at right angles to the direction shown in the drawings, so as to be journaled within, or at least passed through, the

core-pieces of the field-magnets. lalso prefer to provide the motor with the fusible strips N,

adapted to melt out should the current on the main line at any time be excessive. The fusible strips G, I prefer to seat in longitudinal cavities g in an insulating-hub, g, as shown in Fig. 4. By this construction any current which might otherwise injure and burn out a bobbin of the armature would melt the corresponding fusible strip G, and so save the an mature from injury.

I am aware that motors have been made in which more or less current is permitted to pass through the motor to vary its speed and energy; but I am not aware that a motor has been heretofore made in which the whole of the electric currentis always in servicein the motor, but in which the speed and energy of the motor are varied by shifting the entire current through different sizes of wire. The different grades of wire upon the motor are so groupedin quantity with respect to the switch mechanism that the current will meet with the sameresistance at all tiines,whether itbe passing through one grade or another of said wires.

Vhat I claim is V 1. An electric motor having its field-magnet wound with different sizes of wire and means for shifting the entire current from the main line through one or more of said grades of wire at will, thereby varying the speed and energy ofthe motor,substantially as described.

2. An electric motor the field-magnets of which are wound with different grades of wire, the coarsest wire being adjacent to the core, and the grades becoming successively finer as the winding recedes from the core, and means for shifting the entire current from the line through one or more of said different grades of wire at will, thereby regulating the speed and energy of the motor, substantially as described.

3. The combination, with a motor having each of its field-magnets wound with several wires of different sizes, substantially as described, of a switch mechanism, F, permanently connected with the main line and having a series of terminals connected, respectively, with said different grades of wire, the construction being such that the entire cur-' rent may by the switch be directed through one or more of said grades of wire, substantially as described.

In testimony whereof Isign this specification in the presence of two witnesses.

LANDER S. HARRIS.

Witnesses:

M. B. ODOGHERTY, SAMUEL E. THOMAS.

IIO 

